Field of the Invention
The present invention relates to a control method for a clutch of a hybrid electric vehicle. More particularly, the present invention relates to a control method for a clutch of a hybrid electric vehicle that can minimize an operation hydraulic pressure of the clutch by controlling a transfer torque of the clutch in a series and parallel type of hybrid transmission.
Description of Related Art
A hybrid vehicle is a vehicle using two or more different kinds of power sources, and is generally a vehicle that is driven by an engine that obtains a driving torque by burning fuel and a motor that obtains a driving torque from battery power.
A hybrid vehicle may be formed in various structures using an engine and an electric motor as a power source, and a vehicle using an electric motor that directly transfers mechanical power of the engine to a wheel and that is driven with power of a battery as needed is referred to as a parallel hybrid vehicle, and a vehicle that drives an electric motor or that charges electric power to a battery by converting mechanical power of an engine to electrical power through a generator is referred to as a series hybrid vehicle.
Among these hybrid electric vehicles, a hybrid electric vehicle provided with a series and parallel type of hybrid transmission can be operated variably as a series type only using a motor or a parallel type simultaneously using an engine and a motor with a clutch.
The clutch of the series and parallel type hybrid transmission is operated by a hydraulic pressure when the hybrid electric vehicle is operated as a parallel type. Thus, an available transfer torque of the clutch is changed by adjusting the hydraulic pressure depending on a value of a driving torque of the hybrid electric vehicle.
Therefore, available transfer torque of the clutch depending on the hydraulic pressure should be controlled in order to improve efficiency of the series and parallel type of hybrid transmission.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.